Any Wireless Local Area Network (WLAN) device that supports an Institute of Electrical and Electronics Engineers (IEEE) 802.11 Standard (e.g., IEEE Std 802.11-1997, 802.11a, 802.11e, etc.) includes two main parts: 1) a physical (PHY) layer signaling control device; and 2) a medium access control (MAC) device. The function of the PHY device is to transfer data packets over the air interface. Among other things, the function of the MAC device is to fairly control access to the shared air interface.
The minimal MAC protocol consists of two frames: 1) a frame sent from a transmitter to a receiver; and 2) an acknowledgment (ACK) from the receiver that the frame was received correctly. If a transmitter has multiple packets to send to the receiver, some versions of the 802.11 Standard require the transmitter to wait for an ACK after transmission of each packet. In addition, the transmitter must wait for a particular time interval, referred to as the Interframe Space (IFS), after receiving the ACK and before transmitting the next packet.
Other versions of the 802.11 Standard (e.g., IEEE Std 802.11e) support transmission of packets with selective acknowledgement. This feature is referred to as “Block ACK.” The Block ACK feature enables the transmitter to send the next packet to the same receiver without necessarily waiting for an ACK. Instead, after negotiating for access to the air interface, the transmitter sends the first packet, waits an IFS after the end of the first packet, and sends the next packet. After the transmitter has sent all of its packets to the receiver, the transmitter asks the receiver for a response, which indicates an ACK for all of the previously transmitted packets.
Although the Block ACK feature has provided some throughput improvements, developers continue to strive for ways of further increasing throughput. Accordingly, what are needed are methods and apparatus for further improving throughput using burst-mode transmissions.